PolicyStatements - Revision history http://selinuxproject.org/w/?title=PolicyStatements&action=history Revision history for this page on the wiki en MediaWiki 1.23.13 Thu, 28 Mar 2024 11:25:24 GMT RichardHaines at 15:12, 28 January 2015 http://selinuxproject.org/w/?title=PolicyStatements&diff=1753&oldid=prev http://selinuxproject.org/w/?title=PolicyStatements&diff=1753&oldid=prev <p></p> <a href="http://selinuxproject.org/w/?title=PolicyStatements&amp;diff=1753&amp;oldid=851">Show changes</a> Wed, 28 Jan 2015 15:12:05 GMT RichardHaines http://selinuxproject.org/page/Talk:PolicyStatements RichardHaines: New page: = Policy Support Statements = This section contains language statements used to support policy. == module Statement == This statement is mandatory for loadable modules (non-base) and must... http://selinuxproject.org/w/?title=PolicyStatements&diff=851&oldid=prev http://selinuxproject.org/w/?title=PolicyStatements&diff=851&oldid=prev <p>New page: = Policy Support Statements = This section contains language statements used to support policy. == module Statement == This statement is mandatory for loadable modules (non-base) and must...</p> <p><b>New page</b></p><div>= Policy Support Statements =<br /> This section contains language statements used to support policy.<br /> <br /> == module Statement ==<br /> This statement is mandatory for loadable modules (non-base) and must be the first line of any module policy source file. The identifier should not conflict with other module names within the overall policy, otherwise it will over-write an existing module when loaded via the semodule command. The semodule -l command can be used to list all active modules within the policy.<br /> <br /> '''The statement definition is:'''<br /> &lt;pre&gt;<br /> module module_name version_number;<br /> &lt;/pre&gt;<br /> <br /> <br /> '''Where:'''<br /> {|border=&quot;1&quot;<br /> |module<br /> |The module keyword.<br /> <br /> |-<br /> |module_name<br /> |The module name. <br /> <br /> |-<br /> |version_number<br /> |The module version number in M.m.m format (where M = major version number and m = minor version numbers).<br /> <br /> |}<br /> <br /> <br /> '''The statement is valid in:'''<br /> {|border=&quot;1&quot;<br /> |&lt;center&gt;'''Monolithic Policy'''&lt;/center&gt;<br /> |&lt;center&gt;'''Base Policy'''&lt;/center&gt;<br /> |&lt;center&gt;'''Module Policy'''&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;No&lt;/center&gt;<br /> |&lt;center&gt;No&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;'''Conditional Policy (if) Statement'''&lt;/center&gt;<br /> |&lt;center&gt;'''optional Statement'''&lt;/center&gt;<br /> |&lt;center&gt;'''require Statement'''&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;No&lt;/center&gt;<br /> |&lt;center&gt;No&lt;/center&gt;<br /> |&lt;center&gt;No&lt;/center&gt;<br /> <br /> |}<br /> <br /> <br /> '''Example:'''<br /> &lt;pre&gt;<br /> &lt;nowiki&gt;# Using the &lt;/nowiki&gt;''module'' statement to define a loadable module called <br /> &lt;nowiki&gt;# &lt;/nowiki&gt;''bind'' with a version ''1.0.0'':<br /> <br /> module bind 1.8.0;<br /> &lt;/pre&gt;<br /> <br /> == require Statement ==<br /> The require statement is used for two reasons:<br /> <br /> # Within loadable module policy source files to indicate what policy components are required from an external source file (i.e. they are not explicitly defined in this module but elsewhere). The examples below show the usage.<br /> # Within a base policy source file, but only if preceded by the optional Statement to indicate what policy components are required from an external source file (i.e. they are not explicitly defined in the base policy but elsewhere). The examples below show the usage.<br /> <br /> '''The statement definition is:'''<br /> &lt;pre&gt;<br /> require { rule_list }<br /> &lt;/pre&gt;<br /> <br /> '''Where:'''<br /> {|border=&quot;1&quot;<br /> |require<br /> |The require keyword.<br /> <br /> |-<br /> |require_list<br /> |One or more specific statement keywords with their required identifiers in a semi-colon (&lt;nowiki&gt;;&lt;/nowiki&gt;) separated list enclosed within braces ({}). <br /> <br /> The valid statement keywords are:<br /> <br /> * role, type, attribute, user, bool, sensitivity and category. The keyword is followed by one or more identifiers in a comma (,) separated list, with the last entry being terminated with a semi-colon (&lt;nowiki&gt;;&lt;/nowiki&gt;).<br /> * class. The class keyword is followed by a single object class identifier and one or more permissions. Multiple permissions consist of a space separated list enclosed within braces ({}). The list is then terminated with a semi-colon (&lt;nowiki&gt;;&lt;/nowiki&gt;).<br /> <br /> The examples below show these in detail.<br /> <br /> |}<br /> <br /> <br /> '''The statement is valid in:'''<br /> {|border=&quot;1&quot;<br /> |&lt;center&gt;'''Monolithic Policy'''&lt;/center&gt;<br /> |&lt;center&gt;'''Base Policy'''&lt;/center&gt;<br /> |&lt;center&gt;'''Module Policy'''&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;No&lt;/center&gt;<br /> |&lt;center&gt;Yes - But only if proceeded by the optional Statement.&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;'''Conditional Policy (if) Statement'''&lt;/center&gt;<br /> |&lt;center&gt;'''optional Statement'''&lt;/center&gt;<br /> |&lt;center&gt;'''require Statement'''&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;Yes - But only if proceeded by the optional Statement.&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> |&lt;center&gt;No&lt;/center&gt;<br /> <br /> |}<br /> <br /> <br /> '''Examples:'''<br /> &lt;pre&gt;<br /> &lt;nowiki&gt;# A series of require statements showing various entries:&lt;/nowiki&gt;<br /> <br /> require {<br /> role system_r;<br /> class security { compute_av compute_create compute_member check_context load_policy <br /> compute_relabel compute_user setenforce setbool setsecparam setcheckreqprot };<br /> class capability2 { mac_override mac_admin };<br /> }<br /> <br /> &lt;nowiki&gt;#&lt;/nowiki&gt;<br /> require {<br /> attribute direct_run_init, direct_init, direct_init_entry;<br /> type initrc_t;<br /> role system_r;<br /> attribute daemon;<br /> }<br /> <br /> &lt;nowiki&gt;#&lt;/nowiki&gt;<br /> require {<br /> type nscd_t, nscd_var_run_t;<br /> class nscd { getserv getpwd getgrp gethost shmempwd shmemgrp <br /> shmemhost shmemserv };<br /> }<br /> &lt;/pre&gt;<br /> <br /> == optional Statement ==<br /> The optional statement is used to indicate what policy statements may or may not be present in the final compiled policy. The statements will be included in the policy only if all statements within the optional { rule list } can be expanded successfully, this is generally achieved by using a require Statement at the start of the list.<br /> <br /> '''The statement definition is:'''<br /> &lt;pre&gt;<br /> optional { rule_list }<br /> &lt;/pre&gt;<br /> '''Or'''<br /> &lt;pre&gt;<br /> optional { rule_list } else { rule_list }<br /> &lt;/pre&gt;<br /> <br /> '''Where:'''<br /> {|border=&quot;1&quot;<br /> |optional<br /> |The optional keyword.<br /> <br /> |-<br /> |rule_list<br /> |One or more statements enclosed within braces ({}). The list of valid statements is given in a list I have somewhere !!.<br /> <br /> |-<br /> |else<br /> |An optional else keyword.<br /> <br /> |-<br /> |rule_list<br /> |As the rule_list above.<br /> <br /> |}<br /> <br /> <br /> '''The statement is valid in:'''<br /> {|border=&quot;1&quot;<br /> |&lt;center&gt;'''Monolithic Policy'''&lt;/center&gt;<br /> |&lt;center&gt;'''Base Policy'''&lt;/center&gt;<br /> |&lt;center&gt;'''Module Policy'''&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;No&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;'''Conditional Policy (if) Statement'''&lt;/center&gt;<br /> |&lt;center&gt;'''optional Statement'''&lt;/center&gt;<br /> |&lt;center&gt;'''require Statement'''&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> <br /> |}<br /> <br /> <br /> '''Examples:'''<br /> &lt;pre&gt;<br /> &lt;nowiki&gt;# Use of &lt;/nowiki&gt;''optional'' block in a base policy source file.<br /> <br /> optional {<br /> require {<br /> type unconfined_t;<br /> } # end require<br /> <br /> allow acct_t unconfined_t:fd use;<br /> <br /> } # end optional<br /> &lt;/pre&gt;<br /> &lt;pre&gt;<br /> &lt;nowiki&gt;# Use of &lt;/nowiki&gt;''optional'' / ''else'' blocks in a base policy source file.<br /> <br /> optional {<br /> require {<br /> type ping_t, ping_exec_t;<br /> } # end require<br /> <br /> allow dhcpc_t ping_exec_t:file { getattr read execute };<br /> .....<br /> <br /> require {<br /> type netutils_t, netutils_exec_t;<br /> } # end require<br /> <br /> allow dhcpc_t netutils_exec_t:file { getattr read execute };<br /> .....<br /> type_transition dhcpc_t netutils_exec_t:process netutils_t;<br /> ...<br /> <br /> } else {<br /> <br /> allow dhcpc_t self:capability setuid;<br /> .....<br /> } # end optional<br /> &lt;/pre&gt;<br /> <br /> <br /> == policycap Statement ==<br /> Policy database version 22 introduced the policycap statement to allow new capabilities to be enabled or disabled via the policy. In Fedora 10 there are two policy capabilities configured as shown in the SELinux Filesystem section, and are network_peer_controls and open_perms. <br /> <br /> '''The statement definition is:'''<br /> &lt;pre&gt;<br /> policycap capability;<br /> &lt;/pre&gt;<br /> <br /> '''Where:'''<br /> {|border=&quot;1&quot;<br /> |policycap<br /> |The policycap keyword.<br /> <br /> |-<br /> |capability<br /> |The capability identifier that needs to be enabled for this policy.<br /> <br /> |}<br /> <br /> <br /> '''The statement is valid in:'''<br /> {|border=&quot;1&quot;<br /> |&lt;center&gt;'''Monolithic Policy'''&lt;/center&gt;<br /> |&lt;center&gt;'''Base Policy'''&lt;/center&gt;<br /> |&lt;center&gt;'''Module Policy'''&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> |&lt;center&gt;No&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;'''Conditional Policy (if) Statement'''&lt;/center&gt;<br /> |&lt;center&gt;'''optional Statement'''&lt;/center&gt;<br /> |&lt;center&gt;'''require Statement'''&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;No&lt;/center&gt;<br /> |&lt;center&gt;No&lt;/center&gt;<br /> |&lt;center&gt;No&lt;/center&gt;<br /> <br /> |}<br /> <br /> <br /> '''Example:'''<br /> &lt;pre&gt;<br /> &lt;nowiki&gt;# This statement enables the &lt;/nowiki&gt;network_peer_controls to be enabled<br /> &lt;nowiki&gt;# for use by the policy&lt;/nowiki&gt;. <br /> &lt;nowiki&gt;# &lt;/nowiki&gt;<br /> <br /> policycap network_peer_controls;<br /> &lt;/pre&gt;<br /> <br /> == permissive Statement ==<br /> Policy database version 23 introduced the permissive statement to allow the named domain to run in permissive mode instead of running all SELinux domains in permissive mode (that was the only option prior to version 23). Note that the permissive statement:<br /> <br /> * Only tests the source context for any policy denial.<br /> * Can be set by the semanage command as it supports a permissive option as follows:<br /> <br /> ** semanage supports enabling and disabling of permissive<br /> ** mode using the following command:<br /> &lt;pre&gt;<br /> &lt;nowiki&gt;# semanage permissive -a|d type&lt;/nowiki&gt;<br /> &lt;nowiki&gt;# This example will add a new module in /etc/selinux/&lt;/nowiki&gt;<br /> &lt;nowiki&gt;# &lt;policy_name&gt;/modules/active/modules/ called&lt;/nowiki&gt;<br /> &lt;nowiki&gt;# permissive_unconfined_t.pp and then reload the policy: &lt;/nowiki&gt;<br /> <br /> semanage permissive -a unconfined_t<br /> &lt;/pre&gt;<br /> <br /> * Can be built into a loadable policy module so that permissive mode can be easily enabled or disabled by adding or removing the module. An example module is as follows:<br /> &lt;pre&gt;<br /> &lt;nowiki&gt;# This is an example loadable module that would allow the&lt;/nowiki&gt;<br /> &lt;nowiki&gt;# domain to be set to permissive mode.&lt;/nowiki&gt;<br /> &lt;nowiki&gt;#&lt;/nowiki&gt;<br /> <br /> module permissive_unconfined_t 1.0.0;<br /> <br /> require {<br /> type unconfined_t;<br /> }<br /> <br /> permissive unconfined_t;<br /> &lt;/pre&gt;<br /> <br /> '''The statement definition is:'''<br /> &lt;pre&gt;<br /> permissive type_id;<br /> &lt;/pre&gt;<br /> <br /> '''Where:'''<br /> {|border=&quot;1&quot;<br /> |permissive<br /> |The permissive keyword.<br /> <br /> |-<br /> |type_id<br /> |The type identifier of the domain that will be run in permissive mode.<br /> <br /> |}<br /> <br /> <br /> '''The statement is valid in:'''<br /> {|border=&quot;1&quot;<br /> |&lt;center&gt;'''Monolithic Policy'''&lt;/center&gt;<br /> |&lt;center&gt;'''Base Policy'''&lt;/center&gt;<br /> |&lt;center&gt;'''Module Policy'''&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;'''Conditional Policy (if) Statement'''&lt;/center&gt;<br /> |&lt;center&gt;'''optional Statement'''&lt;/center&gt;<br /> |&lt;center&gt;'''require Statement'''&lt;/center&gt;<br /> <br /> |-<br /> |&lt;center&gt;No&lt;/center&gt;<br /> |&lt;center&gt;Yes&lt;/center&gt;<br /> |&lt;center&gt;No&lt;/center&gt;<br /> <br /> |}<br /> <br /> <br /> '''Example:'''<br /> &lt;pre&gt;<br /> &lt;nowii&gt;# This is the simple statement that would allow permissive mode&lt;/nowiki&gt;<br /> &lt;nowiki&gt;# to be set on the httpd_t domain, however this statement is&lt;/nowiki&gt;<br /> &lt;nowiki&gt;# generally built into a loadable policy module so that the&lt;/nowiki&gt;<br /> &lt;nowiki&gt;# permissive mode can be easily removed by removing the module.&lt;/nowiki&gt;<br /> &lt;nowiki&gt;# &lt;/nowiki&gt;<br /> <br /> permissive httpd_t;<br /> &lt;/pre&gt;<br /> <br /> '''semanage(8) Command example:'''<br /> &lt;pre&gt;<br /> semanage permissive -a unconfined_t<br /> &lt;/pre&gt;<br /> <br /> This command will produce the following module in the default &lt;nowiki&gt;&lt;policy_name&gt;&lt;/nowiki&gt; policy store and then activate the policy:<br /> &lt;pre&gt;<br /> &lt;nowiki&gt;/etc/selinux/&lt;policy_name&gt;/modules/active/modules/permissive_unconfined_t.pp&lt;/nowiki&gt;<br /> &lt;/pre&gt;</div> Mon, 30 Nov 2009 14:24:33 GMT RichardHaines http://selinuxproject.org/page/Talk:PolicyStatements